In order to produce a finely crystalline microstructure in abrasive grain it is known that the molten composition should be rapidly frozen. It has been conventional in the art to pour the molten abrasive on a heat resistant surface in the form of a thin slab, to pour into small molds, and to cast onto a cooled rotating cylindrical surface. Such prior art methods which result in the exposure of one surface to the atmosphere produce a product which includes a high degree of porosity at and adjacent such surface.
The present invention achieves the production, for comminution into abrasive grit sized particles, of thin slabs of abrasive oxide material having an extremely small crystal structure and minimizes the production of porous material.